DETROIT: When General Motors engineers and designers started work on the next-generation Corvette, they drew up the usual requirements for the star of American muscle cars. Killer looks. Big engine. Handles like a race car.

But topping the list was something at odds with the roar of the car’s big V-8: gas mileage.

The new Corvette could not be a gas guzzler. Stricter government rules were forcing a leap in fuel economy. If the car burned too much gas, it would trigger fines from regulators and never get built.

“There won’t be a Corvette if we don’t care about fuel economy,” said Tadge Juechter, the car’s chief engineer.

But the 2014 Corvette is here, the first all-new version in nine years. The king of American sports cars, driven by astronauts and celebrated in a Prince song, rolled out Sunday night in Detroit. It will arrive in showrooms this fall.

Getting there was tough for the 1,000-member Corvette team, which gave the car the code name “C7.” GM’s bankruptcy slowed development twice. With each delay, new safety and gas mileage regulations forced changes. The Corvette team overhauled the car: Aluminum replaced steel, super-light rivets held parts together, and the V-8 engine kicked down to four cylinders at highway speeds, saving fuel.

All the changes helped it overcome nine years of government crash safety requirements that could have bloated the car. But even with the lighter materials, the regulations have pushed its weight to a little more than the current base model’s 1,451 kilograms. Still, it’s an engineering achievement. The Corvette is so new that it only shares two parts with the current model.

GM said testing is still being done on the car’s fuel economy, but it’ll be better than the current base model’s 16 mpg (6.8 kpl) in the city and 26 mpg (11.05 kpl) on the highway. Juechter said the window sticker highway mileage won’t reach 30 mpg (12.75 kpl), but he wouldn’t be surprised to see some drivers get that or more.

The car’s usual buyers – men in their mid-50s – will also notice dramatic changes on the outside of the two-seat car. The hood slopes low to slice through the wind. All the vents and scoops have functional purposes like cooling the brakes or transmission.

On the back, designers took cues from the1963 Corvette, with a sloping roof that tapers toward the bottom. The car has a small Stingray badge on each side, complete with gills. And there’s a more modern rendition of the Corvette’s crossed-flag logo.

A 6.2-liter small-block V-8 with 450 horsepower takes the car from zero to 60 mph in under four seconds. That’s at least a few tenths of a second faster than the current base model.

Engineers also redesigned the somewhat-chintzy interior, giving it a jet-cockpit look with leather, carbon fiber and soft plastics.

GM hopes the styling, performance and updated dashboard electronics will expand the car’s appeal to younger buyers. The Corvette’s been a favorite of adrenaline junkies for 60 years. Mercury astronaut Alan Shepard owned one from the first year – 1953.

The company won’t quote a price on the 2014 model. But Juechter said someone who bought the current version can afford the new one. The Corvette starts at $49,600. That is more than $30,000 below what GM considers its chief competitor, the Porsche 911. The car makes a decent profit for GM despite relatively low sales, Juechter said.

GM wouldn’t give sales targets for the new car. Last year it sold only 14,000 of the aging Corvettes, down from over 30,000 the first few years after the current version was rolled out. Porsche sold about 8,500 911s last year.

The prospect of a new ‘Vette has fans waiting anxiously, browsing the Internet for unauthorized photos or drawings. Thousands of aficionados live in the U.S., and even Europe and the Middle East.

John Browning, 70, president of the Renegade Corvette Club of Hollywood, Florida, one of 600 such clubs in the U.S, said some Corvette lovers can’t contain themselves.

“I’ve got one member, he just sold his ’13 in anticipation, to wait for the ’14.”

To many owners, the new Corvette symbolizes the rebirth of America’s auto industry after its near death in 2009, showing the world that it again can lead in technology, styling and performance.

“I think the Corvette is the icon,” said Browning. “As far as I’m concerned you can’t get a better deal.”